With the ever-increasing speed and performance demands on laptop computers, the microprocessor and other components inside the laptop can operate continuously at high temperatures and generate significant amounts of heat. The battery can produce considerable heat during repeated cycles of use and charging that can severely impact both the performance and longevity of the battery and the other components. Keeping the laptop cool, therefore, is a principal concern in extending both the life of the battery and the other electronic components. An internal fan with side duct or bottom openings can be used to cool many of the electronics. Because of its relative size and weight, however, the battery is often isolated from the rest of the operating components in a secondary compartment accessed from the bottom of the laptop, and is thus only exposed to secondary cooling effects.
Due to the fast-approaching ubiquitous nature of laptops, the portable computing devices are often used in environments and manners not anticipated by the designers. For instance, some laptop configurations have bottom cooling vents that require short, permanently-mounted stubs that lift the laptop off a hard support surface to allow cool air to enter and hot air to escape. It is not uncommon, however, to place laptops on soft surfaces such beds, pillows, couches or carpeted floors, such that the stubs sink into the surface and the cooling vents become completely blocked. Even laptops with side vents are not immune to the problem of having the bottom and sides of the laptop completely surrounded by a compliant surface which blocks airflow into and out of the device.